Cutting Device

ABSTRACT

A cutting device ( 10 ) for cutting a pipe ( 32 ) having a pipe wall is disclosed. The cutting device ( 10 ) includes an elongate carrier ( 12 ) having a tool end ( 12.1 ) which is engageable with a power tool and an opposed free end ( 12.2 ). The device ( 10 ) includes a guide wheel ( 16 ) located at the free end ( 12.2 ) of the carrier ( 12 ) which is loosely mounted thereon for rotation relative thereto, having a bearing surface ( 34 ) extending parallel to a longitudinal axis of the carrier ( 12 ). The device ( 10 ) also includes a cutting element ( 14 ) having a peripheral cutting edge ( 36 ) which is located adjacent to the guide wheel ( 16 ) being positioned intermediate the guide wheel  16  and the tool end ( 12.1 ). The cutting element ( 4 ) is of greater transverse dimension than the guide wheel ( 16 ) so that when the bearing surface ( 34 ) bears against an internal surface of the pipe ( 32 ) the distance between the cutting edge ( 36 ) of the cutting element ( 14 ) and the bearing surface ( 34 ) enables the cutting element ( 14 ) to cut through the pipe wall.

FIELD OF THE INVENTION

This invention relates to a cutting device. It also extends to a cuttingelement for a cutting device, a guide or support member for use with acutting device and a method of use of a cutting device.

The invention relates particularly but not exclusively to a cuttingdevice that is suited to cutting pipes including pipes that are alreadyinstalled in a structure. It will therefore be convenient to hereinafterdescribe the invention with reference to this application. However it isto be understood that it is capable of broader application. For exampleit can be used to cut sheets as well as pipes. Where the term “sheets”is used herein it shall be interpreted to cover concrete slabs, panelsor even walls.

BACKGROUND TO THE INVENTION

Generally, to cut a pipe such as a PVC pipe, a user uses a cutting disc.However, if the pipe is built into a floor or a wall, it may not bepossible to gain access to an exterior of the pipe and it is necessaryto cut the pipe from the inside of the pipe. Thus for example U.S. Pat.No. 4,576,070 describes a pipe cutter which requires that the pipecutter be inserted at an angle to a longitudinal axis of the pipe. Thisresults in the side wall of the pipe being cut with a chamfer or beveland will not be desirable. The arrangement is also unstable and anuneven or non-uniform cut could result.

More particularly U.S. Pat. No. 4,576,070 refers to a pipe cutterwherein a power tool imparts rotational torque to a shaft having acircular cutting blade which is oriented orthogonally to the shaft.There is also provided a guide wheel which is journalled onto an end ofthe shaft remote from the cutting tool. In use the cutting blade isaligned at an angle to the longitudinal axis of the pipe being cut sothat it pierces a side wall of the pipe and upon rotation of the cuttingblade it pierces the side wall. The guide wheel is attached to the shaftin such a manner that it does not rotate. Disadvantages of thisconventional pipe cutter include the feature that the guide wheel has toengage the entire internal surface of the pipe to operate and also thatthe guide wheel is located at a substantial distance from the cuttingwheel. Also the cutting wheel is of smaller diameter than the guidewheel. These factors in combination mean that in practice there will begaps between the internal surface of the pipe and the guide wheel aswell as a substantial gap between the internal surface of the pipe andthe cutting wheel. This will severely impair the cutting efficiency ofthe pipe cutter because the guide wheel does not provide a securesupport for the cutting wheel in use. The cutting wheel may laterallymove in an unrestrained manner and cause injury and also cause an unevencut. The cutting wheel will also have a tendency to wobble as the shaftis not oriented in a direction that coincides with the longitudinal axisof the pipe. Also this pipe cutter cannot be easily removed from thepipe after use and could not be used for pipes of different diameters.

Reference may also be made to U.S. Pat. No. 5,815,926 which refers to asimilar arrangement as described above in regard to U.S. Pat. No.4,576,070 with the exception that the guide wheel abuts an adjacent endof the pipe being cut and the cutting wheel which is of smaller diameterthan the guide wheel is also located at a substantial distance from theguide wheel inside the pipe. Because of these structural limitations itis considered that the same disadvantages as discussed above will alsoapply to this reference. In addition the location of the guide wheel ontop of the pipe being cut would be difficult to maintain in practice andthis would cause safety problems. Another disadvantage of thisarrangement is that the pipe being cut before this conventional pipecutter was used had to have an end which was exactly normal to thelongitudinal axis of the pipe. Similar problems would occur with use ofJapanese Patent Publication 2002-187014 which is of similar structure.

Reference also may be made to Japanese Patent Publication 10-216376which describes a pipe cutter which has a cutting wheel adjacent a freeend of the cutter in use. There is also provided a guide wheel which isattached to a rotational shaft of the cutter which is driven by a powertool. However it is noted that the guide wheel is located above thecutting wheel and thus the bearing wheel will bear against the portionof the pipe that is being cut off and removed from the remainder of thepipe. This will impair cutting because the cut part of the pipe willmove during use of the pipe cutter and thus cause an uneven cut. Inaddition to this point the guide wheel will become more ineffective asthe cut continues due to a loss of the bearing surface. When a cut iscompleted a follow through action by the user can cause a wild anduncontained movement of the power tool which can be dangerous.

It would therefore be advantageous to provide a cutter that amelioratesat least some of the disadvantages of the prior art cutters describedabove. It would be advantageous if a cutter could be devised that couldbe operated safely with minimal risk of injury to the operator. It wouldalso be useful if a cutter could be devised that could efficiently andeffectively cut a pipe, particularly when access to the pipe is limited.

SUMMARY OF THE INVENTION

According to one aspect of this invention there is provided a cuttingdevice for cutting a work piece, the cutting device including:

(i) an elongate carrier having a longitudinal axis, a tool end which isengageable with a power tool and a free end;

(ii) a guide or support member located towards the free end of thecarrier which is rotatably attached to the carrier and which has abearing surface extending parallel to the longitudinal axis of thecarrier;

(iii) a cutting element having a peripheral cutting edge which cuttingelement is located intermediate the guide member and the tool end of thecarrier wherein the cutting element is located closely adjacent to theguide member and is of greater transverse dimension than the guidemember thereby forming,

(iv) a peripheral space between the cutting edge of the cutting elementand the bearing surface of the guide member which in use is occupied bythat portion of the blade which cuts through the work piece being cut.

The provision of the space or spacing, e.g. a peripheral spacing, asdescribed above is useful in that it serves as a depth gauge andfacilitates a user cutting the pipe or sheet to the required depth orthickness and stops the cutting element from travelling beyond theconfines of the pipe being cut during use.

The axial distance between the cutting element and the guide member maybe from 0.5-5.0 mm, for example 0.5-1.0 mm. This will also haverelevance to the meaning of “closely adjacent” which means that thecutting element and the guide or support member are only separated by ashort axial distance as exemplified above to provide for formation ofthe space.

In this regard it is pointed out that none of the prior art discussedabove describes features (iii) and (iv) which has the followingadvantages:

(a) the guide or support member by being located internally of thecutting element, e.g. on the other side of the cutting element to thetool end which is attached to the power tool, as shown in the drawingsof the preferred embodiment hereinafter, does not deflect and provides astrong and stable support for the cutting element because itsubstantially engages a surrounding bearing surface of the pipe or sheetbeing cut in use without any gaps being present;

(b) because of (a) above there is no lateral movement of the cuttingelement in use which means that the cutting device of the invention isvery safe to use and thus will comply with all relevant workplace healthand safety regulations in relevant jurisdictions;

(c) it is very easy to separate the cutting device of the invention andthe pipe or sheet being cut after use; and

(d) the guide member having a bearing surface that extends parallel to alongitudinal axis of the carrier and being spaced from the cuttingelement may rotate counter to the direction of rotation or in directionof rotation of the cutting element which in use facilitates displacementof the cutting device about an interior of a pipe being cut and thusmakes the cutting device very efficient in use.

The guide or support member may be in the form of a guide wheel that isloosely mounted on the elongate carrier such that it can rotate relativethereto, e.g. it can rotate freely relative to the carrier. The carriermay be in the form of a rod or shaft.

The cutting device may include a retaining formation that is located atthe free end of the carrier and which has a larger transverse dimensionthan the carrier so as to loosely retain a seat or hub of the guide orsupport member on the carrier.

The carrier may have a threaded portion adjacent the retaining formationand a nut may be threaded onto the threaded portion of the carrier tohold the cutting element on the carrier.

The elongate carrier may have at least one key and the cutting elementmay define at least one keyway that is capable of retaining engagementwith the key on the carrier. Conveniently the elongate carrier mayinclude a pair of keys that engage with a corresponding pair of keywayson the cutting element.

The cutting device may include a disc on the carrier and fast therewiththat incorporates said pair of keys. The disc may be rigidly attached tothe carrier or may be machined out of the carrier.

The cutting device may include a compression ring which engages a matinggroove located in an end cap attached to the free end of the carrier andan aligned groove on the carrier whereby to securely retain the cuttingelement on the elongate carrier.

The cutting device may include a spring clip having a pair of outwardlyextending legs biased away from each other and a pair of adjacent endprojections or tabs located at a free end of each leg which engage withcorresponding notches on the carrier, e.g. towards the free end thereof,to securely retain the guide or support member and the cutting elementon the elongate carrier.

The spring clip may have one end remote from the pair of end projectionsor tabs which is releasably attached to an end cap attached to thecarrier at the free end thereof.

The cutting device may include an end cap attached to the free end ofthe carrier defining an internal bore and a spring located within theinternal bore. The cutting device may also include a longitudinal pinhaving a tapered surface and a pair of transverse pins also having atapered surface whereby the tapered surfaces of the longitudinal pin andeach transverse pin abut each other when each transverse pin is locatedin a corresponding notch or groove of the carrier to securely retain theguide or support member and the cutting element on the carrier.

The cutting device may include an end fastener at the free end of thecarrier which engages with an internal passage of the carrier to providea force against a bushing surrounding the end fastener to ensure thatthe cutting disc and guide or support member are securely retained onthe carrier.

The end fastener may have a screw thread that engages with acomplementary screw thread formed on an internal wall of the carrierforming the internal passage.

According to another aspect of this invention there is provided acutting device including:

(i) an elongate carrier having a longitudinal axis, a tool end that canbe operatively coupled to a power tool and a free end;

(ii) a guide or support member located towards the free end of thecarrier which is rotatably attached to the carrier and which has abearing surface extending parallel to a longitudinal axis of thecarrier; and

(iii) a cutting element having a peripheral cutting edge which cuttingelement is located intermediate the guide or support member and the toolend.

The cutting element may be located closely adjacent to the guide orsupport member.

The cutting device may include any one or more of the features of thecutting device defined above according to the first aspect of theinvention.

The cutting device may include an eccentric cam member defining aninternal cavity and an adjustable collar mounted to the carrier andreceived within the internal cavity of the eccentric cam member, whereinthe cutting element is moved in a similar direction to provide a spacingbetween the guide or support member and the cutting element, whichcorresponds to a desired wall thickness of a pipe or sheet being cut inuse.

The adjustable collar may have a screw threaded shank or shaft to whichis attached an adjustment nut wherein the shank or shaft extends througha side wall of the eccentric cam member and actuation of the nut causessaid movement of the adjustable collar relative to the eccentric cammember having an effective limit governed by abutment of the adjustablecollar with end walls of the internal cavity.

According to another aspect of the invention there is provided a cuttingblade for use with a cutting device for cutting a work piece, e.g.cutting through a side wall of a pipe or through a sheet, which ismountable to a rotatable carrier or shaft, the blade comprising acutting element including a plurality of deflector vanes, each deflectorvane being located inward from a peripheral edge of the cutting elementand the blade defining an aperture therein adjacent to each deflectorvane, whereby in use swarf or dust generated by the pipe or shaft beingcut is directed by each deflector vane through an adjacent aperture awayfrom a face of a user.

The cutting element may be substantially planar and the cutting elementmay be substantially circular.

According to yet another aspect of this invention there is provided aguide or support member for use with a cutting device for cutting aworkpiece, e.g. a side wall of a pipe or a sheet, which is mountable toa rotatable carrier or shaft in conjunction with a cutting element alsomountable to the carrier or shaft, the guide or support memberincluding, a pair of opposed end components and an intermediate assemblyof a plurality of pivotable vanes which are each connected at theirrespective outer ends by a connecting element or strap, whereby each ofthe vanes is movable from an inner location to an outer location whichdefine inner and outer limits of a transverse dimension of the guide orsupport member whereby to adjust the diameter of the guide or supportmember.

Each vane may be arcuate and each of the vanes may have a similarcurvature having one concave side and an opposed convex side, e.g. whenthe guide or support member is viewed from one end.

Each vane may define a slot and respective outer ends of adjacentconnection elements may be capable of sliding displacement in the slotupon pivotal movement of each vane whereby to adjust the diameter of theguide or support member.

Respective inner ends of each vane may be pivotably attached to one oreach end component. Further respective inner ends of each vane have aninternal aperture for determining the limits of pivotal movement of eachvane.

According to yet another aspect of this invention there is provided amethod of use of a cutting device to cut a work piece which includes thefollowing:

(a) attaching one end of a rotatable elongate carrier to a power toolwhich at another end has a guide member rotatably attached thereto and acutting element attached to the rotatable carrier inwardly of the guidemember wherein said cutting element also has a greater transversedimension than the guide member and is located closely adjacent to theguide member so as to form a peripheral space between the guide memberand the cutting element;

(b) operating the power tool to cause rotation of the rotatable carrierwherein the guide member rotates along a surface of the work piece beingcut, wherein said bearing surface is parallel to a longitudinal axis ofthe rotatable carrier; and

(c) cutting through the work piece.

The work piece may be a pipe in which case cutting through a side wallof the pipe may comprise extending the cut around the full circumferenceof the pipe with the guide member rotating along an inner surface of thepipe so that the side wall of the pipe is completely severed from theremainder of the pipe. The longitudinal surface of the carrier may beparallel to and spaced from a longitudinal axis of the pipe.

Instead the work piece may be a substantially planar sheet of material.

The guide member may rotate counter to the direction of rotation of thecutting element. Instead the guide member may rotate in the samedirection as the cutting element but independently thereof and at aslower speed of rotation.

According to yet another aspect of this invention there is provided amethod of cutting a pipe to remove an end region of the pipe, the methodincluding:

providing a rotatable elongate carrier having one end for coupling to apower tool and a guide member rotatably attached thereto towards anotherend and a cutting element attached to the rotatable carrier in betweenthe guide member and said one end, the cutting element having a greatertransverse dimension than the guide member,

rotating the rotatable carrier whereby to rotate the cutting elementwhereby to enable it to cut through the pipe, and displacing the guidemember around an inner surface of the pipe whereby to guide the cuttingelement around the pipe while cutting the pipe along a cutting linetransverse to the axis of the pipe.

Rotating the carrier may comprise rotating the carrier and thereby alsothe blade at high speed by operatively coupling it to a power tool.

Displacing the guide member may guide the cutting element around thefull circumference of the pipe whereby to cut the pipe throughcompletely and remove the end region of the pipe.

Displacing the guide member may comprise displacing it around the pipesurface in a direction that is counter to the direction of rotation ofthe cutting element.

The guide member may include a bearing surface and displacing the guidemember may comprise contacting the bearing surface with an internalsurface of the side wall of the pipe being cut or an adjacent surface ofa sheet being cut.

BRIEF DESCRIPTION OF THE DRAWINGS AND DETAILED DESCRIPTION OF THEEMBODIMENTS ILLUSTRATED IN THE DRAWINGS

A cutting device for cutting pipes and a method for cutting pipes inaccordance with this invention may manifest itself in a variety offorms. It will be convenient to hereinafter describe several embodimentsof the invention in detail with reference to the accompanying drawings.The purpose of providing this detailed description is to instructpersons having an interest in the subject matter of the invention how tocarry the invention into practical effect. However it is to be clearlyunderstood that the specific nature of this detailed description doesnot supersede the generality of the preceding broad description. In thedrawings:

FIG. 1 refers to an assembled view of a first embodiment of a cuttingdevice of the invention;

FIG. 2 refers to an exploded perspective view of the invention of thecutting device shown in FIG. 1;

FIG. 3 shows a sectional view of the cutting device of FIG. 1 in use incutting a pipe and FIG. 4 is a side view of the arrangement shown inFIG. 3;

FIG. 5 shows an exploded perspective view of a second embodiment of theinvention wherein use is made of a compression ring;

FIGS. 6A, 6B and 6C are sectional views of the cutting device shown inFIG. 5 showing the installation of the end cap to the rotatable shaft;

FIG. 7 is an exploded perspective view of a third embodiment of thepresent invention;

FIG. 8 is an exploded perspective view of a fourth embodiment of thepresent invention;

FIGS. 9, 10 and 11 are sectional views of the embodiment shown in FIG.8;

FIG. 12 refers to an exploded perspective view of a fifth embodiment ofthe present invention;

FIGS. 13, 14 and 15 refer to sectional views of the embodiment shown inFIG. 12;

FIG. 16 refers to an exploded perspective view of a fifth embodiment ofthe invention;

FIGS. 17, 18 and 19 are sectional view of the embodiment shown in FIG.16;

FIG. 20 represents an exploded perspective view of a sixth embodiment ofthe invention;

FIGS. 21 and 22 are sectional view of the embodiment shown in FIG. 20;

FIG. 23 represents an exploded perspective view of the seventhembodiment of the invention;

FIGS. 24, 25 and 26 represent front views of the embodiment shown inFIG. 23;

FIG. 27 refers to a front view of the embodiment shown in FIG. 23 withthe end cap removed;

FIGS. 28, 29 and 30 represent cutting discs for use in the invention foruse in directing dust and swarf away from the user;

FIG. 31 represents an exploded perspective view of a modified guidemember for use in the invention;

FIGS. 32, 33, 34 and 35 show the guide wheel of FIG. 31 and the dustextractor cutting disc of FIG. 30 mounted to a rotatable shaft; and

FIG. 36 shows the cutting apparatus of FIGS. 32, 33, 34 and 35 incutting a flat sheet or panel.

In the drawings, reference numeral 10 generally designates an embodimentof a pipe cutting device.

The device 10 includes an elongate carrier in the form of a rod or shaft12 having a proximal end or free end 12.2, and a distal end or tool end12.1 (i.e. engageable by a power tool). A cutting element in the form ofa cutting disc 14 is arranged on the rod 12 to be rotatably fast with orfixedly attached to the rod 12. The cutting disc 14 is arranged closelyadjacent to but spaced from a guide member in the form of a guide wheel16 which is carried rotatably by the rod 12. The guide wheel 16 is,further, positioned closely adjacent surface 14.1 (FIG. 2) of thecutting disc 14 which has a central aperture 19.

An attaching formation in the form of a shank portion 18 is defined atthe proximal end 12.1 of the rod 12. The shank portion 18 is received ina gripping element such as a chuck (not shown) of a power tool. Thepower tool is, for example, a hand drill.

A retaining formation in the form of a button 20 is mounted at thedistal end 12.2 of the rod 12. A boss 22 is defined adjacent to thebutton 20. The boss 22 has a larger diameter than the rod 12 but asmaller diameter than the button 20. The guide wheel 16 defines a seator hub 24 within which the button 20 is received to retain the guidewheel 16 on the rod 12 with the guide wheel 16 being carried on the boss22.

The rod 12 has a threaded portion 26 arranged adjoining the boss 22. Thecutting disc 14 is held captive on the rod 12 by a nut 28 that engagesthe threaded portion 26 of the rod 12 with a screw thread engagement.The device 10 includes a pair of lock washers 30. The washers 30 arearranged on opposite sides of the cutting disc 14 and serve to lock thecutting disc 14 to the rod 12 so that the cutting disc 14, in use,rotates with the rod 12 under the action of the power tool to which therod 12 is connected.

The cutting disc 14 has a diameter which is less than the diameter of apipe 32 (FIGS. 3 and 4) to be cut. The guide wheel 16, in turn, has adiameter which is less than the diameter of the cutting disc 14. Theguide wheel 16 defines a bearing surface 34 which extends parallel to alongitudinal axis of the rod 12. A peripheral space 36 defined between acutting edge of the cutting disc 14 and the bearing surface 34 of theguide wheel 16 serves as a depth gauge and facilitates a user cuttingthe pipe to the required depth as shown in FIG. 4 of the drawings.

The cutting disc 14 is any suitable abrasive cutting disc such as atungsten-carbide disc or a diamond tipped disc.

The device 10 is sold as a pre-assembled unit or can be provided as anumber of components which can be assembled together, e.g. in kit form,with the rod 12, the nut 28, the pair of washers 30, one or more cuttingdiscs 14, which may be of different diameters, and one or more guidewheels 16 of different diameters. By having guide wheels of differentdiameters the depth of cut that can be made with the cutting device canbe varied. If the device 10 is provided as a kit, a required size ofcutting disc 14 and guide wheel 16 are selected and mounted on the rod12. The guide wheel 16 is received on the boss 22 with the button 20being received in the seat 24 of the cutting wheel 16. The guide wheelalso includes apertures 24A defined therein for air flow and to reducethe amount of material used in the guide wheel 16. It also includes acentral aperture 24B which is passed over the rod 12 to mount the guidewheel 16 on the rod 12.

The boss 22 is received within the central aperture 24B of the guidewheel 16 a loose fit within the guide wheel 16 so that the guide wheel16 can rotate relative to the rod 12. The selected cutting disc 14 ismounted on the rod 12 adjacent to the guide wheel 16 and is secured inposition by the nut 28. The combination of the nut 28 being screwed onto the threaded portion 26 with the provision of the lock washers 30serve to lock the cutting disc 14 to the rod 12. The disc 14 is fastwith the rod 12 and rotates together with the rod 12.

In the example illustrated, the device 10 is used to cut a pipe 32 belowa floor 38 in a building. It is noted that the diameter of the cuttingdisc 14 is less than the diameter of the pipe 32 to be cut.

The power tool (not shown) to which the device 10 has been attached isoperated to rotate the rod 12 and the cutting disc 14 attached to therod 12. An edge of the cutting disc 14 is placed against an innersurface 40 of the pipe 32 and first cut 42 is made in a wall of the pipe32. The cutting disc 14 cuts to a depth governed by the space 36 betweenthe edge of the cutting disc 14 and the bearing surface 34 of the guidewheel 16. In other words, the cutting disc 14 cuts through the wall ofthe pipe 32 until the bearing surface 34 bears against the internalsurface of the pipe 32 as shown in FIG. 4 of the drawings.

In the illustrated embodiment, it is assumed that the rod 12 is rotatedclockwise as shown by arrow 44 in FIG. 3 of the drawings. Due to theguide wheel 16 bearing against the internal surface 40 of the pipe 32after the required depth of cut 42 has been attained, acounter-rotational movement of the device 10 is set up about thelongitudinal axis of the pipe 32 as shown by arrow 46 in FIG. 3 of thedrawings. This assists the user in cutting the pipe 32 and maintaining auniform height of cut. It will also be appreciated that the guide wall16 may also rotate in the same direction as cutting disc 14.

Moreover, when the cut has been completed about the circumference of thepipe 32, the guide wheel 16 serves to restrain the device 10 from flyingout laterally from the pipe 32 which, but for the presence of the guidewheel 16, could otherwise occur. Thus, the likelihood of the userinjuring himself or herself or causing damage to surrounding structureis obviated.

It will therefore be appreciated that the provision of the guide wheel16 inwardly of the cutting disc 14 serves three functions at least.Firstly, the guide wheel 16 functions as a depth gauge to control thedepth of the cut of the wall of the pipe 32. The guide wheel 34 furtherserves to assist in the counter-rotational movement of the device 10about the internal surface 40 of the pipe 32 to form a circumferentialcut in the pipe 32. Thirdly, the guide wheel 16 serves to restrain thedevice 10 after completion of the cut.

It is therefore an advantage of the described embodiment that a pipecutting device 10 is provided which enables a user to perform an even,uniform cut which is at right angles to the longitudinal axis of thepipe 32. The provision of the guide wheel 16 serves as a depth gauge toenable the user to control the depth of the cut. In addition, theprovision of the guide wheel 16 advantageously serves to assist inrotating the device 10 about the longitudinal axis of the pipe duringthe cutting operation. The guide wheel 16 also serves to restrain thedevice 10 against lateral movement beyond the confines of the pipe 32after completion of the cutting operation 32.

It is a further advantage of the described embodiment that, if desired,different diameters of cutting discs 14 and guide wheel 16 can bemounted on the rod 12 in a simple operation by unscrewing the nut 28from the threaded part 26 of the rod 12. With the describedconfiguration of the rod 12, the entire rod 12 need not be threaded soit is a reasonably simple and quick matter to remove and replace the nut28.

As described above, the device 10 could be sold in sets where a rod 12is provided with various sizes of cutting discs 14 and/or guide wheels16. In addition, the set could merely have replacement cutting discs 14so that blunt cutting discs 14 can be replaced by sharp cutting discs14.

While the embodiment has been described with reference to a pipe 32 ofcircular cross-section, it will be appreciated that the device 10 could,conceivably, be used with pipes of other cross-section albeit with lowerefficiency.

In FIGS. 5, 6A, 6B and 6C there is shown a further embodiment of theinvention showing cutting device 10A which includes similar componentsas described above using the same reference numerals. In this embodimentthere is provided an end cap 22A having an internal groove 22B forsupporting a snap or compression ring 53 made of an elastomeric orflexible material which can be C shaped as shown. There is also shown adisc 47 which is welded or which is a permanent part of shaft 12 formedby a machining operation. Disc 47 is also provided with keyway 48 andgroove 55 which also supports snap ring 53 as shown in FIGS. 6A, 6B and6C. Cutting disc 14A is provided with central aperture 19 having top andbottom keyways or recesses 49A. End cap 22A is also provided with flange22C and end wall 54A. There is also provided lever aperture 54.

The process of installing the end cap 22A on shaft 12 is shownsequentially in FIGS. 6A, 6B and 6C and by the arrows in FIG. 6A and 6B.The snap ring 53 is held captive in groove 22B and as end cap 22A ispressed onto shaft 12 its tapered lead in surface 56 collides with snapring 53. When the pressing force on end cap 22A is greater than thenatural resistive force associated with snap ring 53 the snap ring 53will reduce its diameter via physical displacement to a point where theinternal diameter of end cap 22A equals the outside diameter of snapring 53. At this stage the end cap 22A can slide onto shaft 12 untilsnap ring 53 meets with internal groove 22B. At this point snap ring 53will return to an outside diameter that equals the diameter of groove22B. At this stage the design of groove 22B will be such that snap ring53 will be providing a positive force against the internal surface ofgroove 22B which is then translated to cutting disc 14A. This forceenables cutting disc 14A to fully engage with keys 48 and thus allowsguide wheel 16 to rotate around the longitudinal axis of end cap 22Afreely. This force also prevents cutting disc 14A, end cap 22A and guidewheel 16 from sliding off shaft 12. To release the end cap from theshaft 12 the same force is applied to end cap 22A via a lever insertedin slot 54 and the same process occurs in reverse. In FIG. 6C it will benoted that flange 22C engages in peripheral space 57.

The above described embodiment in FIGS. 5 and 6A, 6B and 6C is usefulfor cutting device 10A on pipes or sheets made from different plasticsmaterials such as HDPE or PVC or metals including copper and stainlesssteel or other materials including ceramics and earthenware.

In FIG. 7 there is shown another embodiment in relation to cuttingdevice 10B which has top and bottom projections or keys 50A on shaft 12adjacent boss 22 which pass through as is the case with the embodimentof FIG. 5 keyways 51 of washer 30A and top and bottom keyways orrecesses 49A of keyway 49. Again this is an example of a quick releasecoupling initiated by removal of nut 28.

Another embodiment is shown in FIGS. 8, 9, 10 and 11 showing cuttingdevice 10C wherein use is made of a spring clip 56 having arms 57 andend projections 58. There is also provided a cutting disc 14C which isattached to shaft 12 having keyways 59 which engage with keys 60 onlocking disc 61. There is also provided tubular bushing 62. Again thisis another example of a quick release coupling wherein spring clip 56may be quickly dismantled by use of pliers or a screwdriver (not shown).In FIG. 9 shaft 12 is provided with a hollow passage 63 foraccommodation of spring clip 56.

In cutting device 10C the spring clip 56 is in the form of a springsteel clip and is designed to provide a force that encapsulates guidewheel 16 and cutting disc 14C. This is achieved by each of arms 57 beingbiased inwardly. As shown in FIGS. 9-10, by means of depressing endprojections or tabs 58, the clip 56 may be inserted into hollow interior63 of shaft 12 inside bushing 62. When projections 58 are released theclip 56 may be retained in position inside hollow interior 63 of shaft12 and hollow passage 64 of shaft 12 as shown with projections 58engaging in retaining notches 65 as shown in FIG. 11. This enables thecutting disc 14A to be fully engaged and securely retained by keys 60 onshaft 12.

In the embodiment of FIGS. 12-15, there is shown cutting device 10Dwhich has shown a similar arrangement as described above for FIGS. 8-11using a spring clip 56A which has arms 57A and end projections 58A. Clip56A also has aperture 66 for retention of screw 67. There is alsoprovided end cap 68 to which spring clip 56A is attached by retainingscrew 67. End cap 68 also has lever slot 69 in head 70 and shank 71.There is also provided a hollow bush 72 with end projections 73 whichengage with mating slots 74 in end cap 68. Bush 72 has flange 75 withkeyways 76 which mate with keyways 77 of cutter disc 14D. Both keyways76 and 77 mate with keys 78 on disc 79 integral with shaft 12 to providea positive force between the end cap 68 and the cutting disc 14D. Whenfirst engaging the end cap 68 into the shaft 12, the locking arms 57Acollide with the tapered lead-in 80 on the shaft 12 as shown in FIGS.13-14. At this point when the pressing force on the end cap 68 is largerthan the combined friction and spring clip 56A bending forces, thelocking arms 57A begin to displace normal toward the centre axis of theshaft 12. When the locking arms 57A meet with internal groove 81 towardthe base of the shaft internal cavity 72A, the spring clip 56A resistivebending force translates to projections 58A when they press against thetapered wall 84 of groove 81, driving the end cap 68 further inwardalong the axis of the shaft 12. With the end cap 68 fully engaged, thereis always a positive force provided by the spring clip 56A translated tothe tapered wall 84 on groove 81. This force is then translated througha flat surface 83 of the end cap 68 which is perpendicular to the shaftaxis. This surface 83 presses against the shaft bushing 72 which thenpresses against the cutting disc 14D providing a positive force thatenables the cutting disc 14D to be fully engaged on the shaft key 78. Anadded feature of cutter device 10D is that as the shaft 12 rotates it isproviding a centripetal force to the locking arms 57A. As thisacceleration increases so too does the centripetal force whichtranslates to the tapered wall 84 on the inner groove 81 of the shaftincreasing the pressure applied to the cutting disc 14D, thereforeincreasing the force required to displace the cutting disc 14D in itsoperation as shown in FIG. 15.

In the embodiment shown in FIGS. 16-19, a similar arrangement is shownas in FIGS. 12-15 with the exception that spring clip 56A is replacedwith compression spring 86, transverse tapered locking pins 87 and endpin 88. Cutter device 10E functions to provide a positive force betweenthe end cap 68 and the cutting disc 14D. When first engaging end cap 68into the shaft cavity 82 the tapered locking pins 87 collide with thetapered lead-in 80 in shaft cavity 82. At this point when the pressingforce on the end cap 68 is larger than the combined friction and springforces, the tapered locking pins 87 begin to displace normal toward thecentre axis of the shaft 12. This displacement translates intolongitudinal displacement of the tapered spring end pin 88 via the tapershared between mating surfaces 89 and 90 on the locking pins 87 and thetapered spring end pin 88 as shown in FIGS. 17-18. This in turndisplaces the compression spring 86 which is providing the resistiveforce. When the tapered locking pins 87 meet with internal groove 81toward the base of the shaft cavity 82, the spring force translates tolocking pins 87 which then presses against tapered wall 84 driving theend cap 68 further inward along the axis of the shaft 72. With the endcap 68 fully engaged there is always a positive force provided by thecompression spring 86 translated to the tapered wall 84. This force isthen translated through flat surface 83 of the end cap 68 which isperpendicular to the shaft 12 axis. This end cap surface 83 pressesagainst the shaft bushing 72 when then presses against the cutting disc14D providing a positive force that enables the cutting disc 14D to befully engaged on the shaft key 78 as shown in FIG. 19. An added featureof cutter assembly 10E is that as the shaft 12 rotates it is providing acentripetal force to the locking pins 87. As this acceleration increasesso to does the centripetal force which translates to the tapered wall 84increasing the pressure applied to the cutting disc 14D, thereforeincreasing the force required to displace the cutting disc 14D whilst inoperation.

The cutting device 10F shown in FIGS. 20, 21 and 22 uses the cutter disc14F with the keyways 91 that engage with the keys 78. There is alsoprovided a fastener 92 having a shank 93 with a screw thread thatengages an internal thread 94 of adjacent end 95 of shaft 12 as shown inFIGS. 21-22. Fastener 92 also has head 93A, flange 96 and screwdriverslot 94. There is also shown bushing 72A. Fastener 92 is used to providea force that encapsulates the guide wheel 16 and the cutting disc 14, bymeans of engaging with internal thread 94. The fastener 92 when fullyengaged provides a force against a shaft bushing 72A that in turntranslates that force to the cutting disc 14F. This force enables thecutting disc 14F to fully engage with the key 78 on the shaft 12 andallows the guide wheel 16 to rotate around the longitudinal axis of theshaft 12 freely. This force also prevents the cutting disc 14F, bushing72A and guide wheel 16 from sliding off the shaft 12. FIG. 22 showsflange 97 of bushing 72A interposed between cutter disc 14F and hub 24of guide wheel 16.

In FIG. 23 there is provided cutting device 10G having an eccentricadjustable cam 100, an adjustment nut 99 which is mounted on screwthreaded shaft 101 of shaft connection collar 102, an oval shapedaperture 103 for retention of shaft connection collar 102 and a slot104. The aperture 103 has opposed end walls 103A which determine theextent of movement of collar 102 in aperture 103. There is also shown anattachment aperture 106 of eccentric adjustable cam 100. The operationof cutting device 106 is shown in FIGS. 24, 25 and 26. There is alsoshown dust collection vanes 107 for directing dust in use away from theoperator of cutting device 10G.

The cutting device 10G can be used in relation to a variety of wallthicknesses and thus functions as a wall thickness gauge. The operationuses eccentric adjustable cam 100 in combination with guide wheel 16 andcutting disc 14G being loosely fitted to shaft 12. By turning adjustmentnut 101 in either direction the centre of shaft axis will change inrelation to guide wheel 16. Thus the shaft axis may move from a centralposition shown in FIG. 25 to an eccentric position dependent on thenumber of turns of nut 100 shown in FIGS. 25 and 26. This eccentricitycauses the centre of force to move in relation to guide wheel 16creating a moment of force around the rotating shaft 12. This in turnallows the guide wheel 16 to be naturally positioned at the desiredgauge of wall thickness independent of the position of cutting disc 10Fas shown in FIGS. 26 and 27.

In FIG. 27 there is shown an assembled view of cutting device 10. Thereis shown the rotating shaft centre 108 and the line of force 109 isperpendicular to the medium being cut. There is also shown the wallthickness indicated by 110.

In FIG. 28 there is shown one form of cutting disc 111 which inoperation is of directional design to provide a low pressure vortex tocreate a vacuum surrounding the cutting disc 111 which is dependent onrotational direction. This cutting disc and its elevated deflectors 113is effective to draw the dust and swarf 113A away from the surface ofthe article being cut and down through apertures 114 adjacent eachdeflector 113. This cutting disc 111 is effective in extraction of dustand swarf away from the face of the user.

In FIG. 29 there is shown cutting disc 115 which again is of aunidirectional design to provide a low pressure area towards the centre19 of cutting disc 115 independent of rotational direction. This designis effective to draw dust and swarf away from the article being cut anddown through apertures 114A adjacent deflector vanes 113A.

In FIG. 30 there is shown a unidirectional cutting disc 116 whichprovides a low pressure area close to cutting face 112 independent ofrotational direction. This design is effective to draw the dust andswarf away from the surface of the article being cut and throughapertures 118 adjacent deflectors 117 and thus away from the face of theuser.

In FIG. 31 there is shown a variable diameter guide wheel 16A used forcontrolling depth of cut for cutting devices. Guide wheel 16A comprisesof a top disc component 120, a bottom disc component 120A, several vanecomponents 121 and several curved vane connection components 122. Guidewheel 16A uses a worm drive 123 that controls the amount of rotation ofthe top component 120 performs in relations to the bottom component120A. When the worm drive 123 is actioned the top disc component 120rotates causing the internal pins 125 that are connected to the top disccomponent 120 and are held captive in a slot 126 to press against anadjacent surface of the slot 126. The vane components 121 are also heldcaptive to the bottom disc component 120A by means of pins 124 whichpass through apertures 127 which also act as a pivot point for the vanecomponents 121. The vane components 121 are able to rotate around thepivot point 127 therefore changing the outside diameter of the vanecomponents 124. The curved vane connection components 122 are joined tothe vane components 121 at mutually adjacent ends via a pin 128 shown inphantom again acting as a pivot point. Each of components 121 andadjacent ends of components 122 are joined by a pin 128 which moves inslot 129. This slot 129 allows the curved vane connection components 122to move tangentially to that slot thus maintaining a connection betweeneach vane component 121.

There is also provided locating projections 130 of bottom disc component120A which each locate in mating recesses 131 of top disc component 120.The worm drive 123 is contained in housing 132 and actioned by ascrewdriver (not shown) engaging slots 133 and 134.

In FIGS. 32, 33, 34 and 35 there is shown the guide wheel 16A mounted onshaft 12 in combination with dust extraction disc 116. This isaccomplished the use of end cap 68 as shown in FIGS. 33, 34 and 35.

In FIG. 36 there is cutting device 10H shown in FIGS. 32-35 utilized incutting a planar panel 136. The cutting device 10H has already formedthe cutting line 137 shown in the drawings.

One advantage of the cutting device described above with reference tothe drawings is that the guide or support member that is in the form ofthe guide wheel 16 is located on the other side of the blade 14 to thepower end 12.1 that is operatively coupled to a power tool. Applicanthas found that the cutting device can be mounted in a very stable mannerin position on a work piece when the blade is rotating at high speedwith this arrangement. Without being bound by theory Applicant believesthat this is due to the support provided by the guide wheel on the otherside of the blade to the rotational drive imparted by the power tool.This feature results in a much more stable and comfortable operation ofthe cutting device by the user. It also helps the user to make a muchmore precise and accurate cut with the power tool. This is importantbecause the cutting device can be used to cut off pipe sections thatproject above a floor or the like and it is highly desirable that thisis done accurately and precisely.

It will of course be realized that the above has been given only by wayof illustrative example of the invention and that all such modificationsand variations thereto, as would be apparent to persons skilled in theart, are deemed to fall within the broad scope and ambit of theinvention as is herein set forth.

1. A cutting device including: (i) an elongate carrier having a tool endwhich is engageable with a power tool and a free end; (ii) a guide orsupport member located towards the free end of the carrier which isrotatably attached to the carrier and which has a bearing surfaceextending parallel to a longitudinal axis of the carrier; (iii) acutting element having a peripheral cutting edge which cutting elementis located intermediate the guide member and the power tool end of thecarrier wherein the cutting element is located closely adjacent to theguide member and is of greater transverse dimension than the guidemember thereby forming, (iv) a peripheral space between the cutting edgeof the cutting element and a bearing surface of the guide member whichin use is occupied by that portion of the blade which cuts through thework piece being cut.
 2. A cutting device as claimed in claim 1 whereinthe axial distance between the cutting element and the guide or supportmember is 0.5-5.0 mm.
 3. A cutting device as claimed in claim 2, whereinthe axial distance between the cutting element and the guide or supportmember is 0.5-1.0 mm.
 4. A cutting device as claimed in claim 1, whereina retaining formation is located at the free end of the carrier whichhas a larger transverse dimension than the carrier so as to looselyretain a seat or hub of the guide or support member.
 5. A cutting deviceas claimed in claim 4, wherein the carrier has a threaded portionadjacent the retaining formation and a nut is threaded onto the threadedportion of the carrier to hold the cutting element on the carrier.
 6. Acutting device as claimed in claim 1, wherein the elongate carrier hasat least one key and the cutting element defines at least one keywaythat is capable of retaining engagement with the key on the carrier. 7.A cutting device as claimed in claim 6, having a pair of keys on thecarrier that engage with a corresponding pair of keyways on the cuttingelement.
 8. A cutting device as claimed in claim 7, wherein there isprovided a disc rigidly attached to the carrier or machined out of thecarrier which also incorporates said pair of keys.
 9. A cutting deviceas claimed in claim 1, wherein there is provided a compression ringwhich engages a mating groove located in an end cap attached to the freeend of the carrier and an aligned groove on the carrier to securelyretain the cutting element on the elongate carrier.
 10. A cutting deviceas claimed in claim 1, wherein there is provided a spring clip having apair of outwardly extending legs biased away from each other and a pairof adjacent end projections or tabs located at a free end of each legwhich engage with corresponding notches on the carrier to securelyretain the guide or support member and the cutting element on theelongate carrier.
 11. A cutting device as claimed in claim 10, whereinthe spring clip has one end remote from the pair of end projections ortabs which is releasably attached to an end cap attached to the carrierat the free end thereof.
 12. A cutting device as claimed in claim 1,where there is provided an end cap attached to the carrier at the freeend thereof which has a spring located in an internal bore of the endcap.
 13. A cutting device as claimed in claim 12, including alongitudinal pin having a tapered surface and a pair of transverse pinsalso having a tapered surface whereby the tapered surfaces of thelongitudinal pin and each transverse pin abut each other when eachtransverse pin is located in a corresponding notch or groove of thecarrier to securely retain the guide or support member and the cuttingelement on the carrier.
 14. A cutting device as claimed in claim 1,wherein there is provided an end fastener at the free end of the carrierwhich engages with an internal passage of the carrier to provide a forceagainst a bushing surrounding the end fastener to ensure that thecutting disc and guide or support member are securely retained on thecarrier, and wherein the end fastener is screw threadedly attached tothe internal passage.
 15. A cutting device including: (i) an elongatecarrier having a longitudinal axis, a tool end engageable with a powertool and a free end; (ii) a guide or support member located towards thefree end of the carrier which is rotatably attached to the carrier andwhich has a bearing surface extending parallel to the longitudinal axis;and (iii) a cutting element having a peripheral cutting edge whichcutting element is located intermediate the guide or support member andthe tool end.
 16. A cutting device as claimed in claim 15, including aneccentric cam member defining an internal cavity and an adjustablecollar mounted to the carrier and received within the internal cavity ofthe eccentric cam member, wherein the cutting element is moved in asimilar direction to provide a spacing between the guide or supportmember and the cutting element, which corresponds to a desired wallthickness of a pipe or sheet being cut in use.
 17. A cutting device asclaimed in claim 16, wherein the adjustable collar has a screw threadedshank or shaft to which is attached an adjustment nut wherein the shankor shaft extends through a side wall of the eccentric cam member andactuation of the nut causes said movement of the adjustable collarrelative to the eccentric cam member having an effective limit governedby abutment of the adjustable collar with end walls of the internalcavity. 18-23. (canceled)
 24. A method of use of a cutting device to cuta work piece which includes the following: (a) attaching one end of arotatable elongate carrier to a power tool which at another end has aguide member rotatably attached thereto and a cutting element attachedto the rotatable carrier inwardly of the guide member wherein saidcutting element also has a greater transverse dimension than the guidemember and is located closely adjacent to the guide member so as to forma peripheral space between the guide member and the cutting element; (b)operating the power tool to cause rotation of the rotatable carrierwherein the guide member rotates along a surface of the work piece beingcut, wherein said bearing surface is parallel to a longitudinal axis ofthe rotatable carrier; and (c) cutting through the work piece.
 25. Amethod of use of a cutting device according to claim 24, wherein theguide member counter rotates to the direction of rotation of the cuttingelement.